Apparatus for burning powdered fuel



Oct. 26, 1937. D. VAN LAW APPARATUS FOR BURNING POWDERED FUEL 2 Sheets-Sheet 1 Filed Dec. 27, 1932 INVENTOR.

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ATTORNEYS Oct. 26, 1937. D. VAN LAW APPARATUS FOR BURNING POWDERED FUEL Filed Dec. 27, 1932 2 Sheets-Sheet I INVENTOR.

BY 4 W x/ml ATTORNEYS Patented Oct. 26, 1937 r UNITED STATES PATENT OFFICE APPARATUS" FOR BURNING POWDERED 1 V FUEL V v Durbin Van Law, Denver, Colo; assignor to Powderco, 1110., Denver, Colo.

Application'December 217, 1932, Serial No. 649,008 8 Claims. (01; 110-2s) This invention relates to apparatus for burnhousing I! which is fastened toand exteriorly of mg powdered fuel; and more particularly to certhe furnace wall by bolts l8.

tain new anduseful improvements in the con- The housing is hollow to provide'an air cham structions disclosed in my application for Patent ber' 19, and it has its outer surfaces'b'reen- Serial No; 593,006, filed February 15; 1932. 5 covered ports 25' communicating with tl'ie cliamt is-a'n object of the present invention to-proher, the effective size of which -is controlled 'by-a motetheefiici'ency ofthe burner shown andderevolvingshutter 2 l.-- At the lower portionot the scribed in the above-mentioned application" for housing is a valve chamber 22 in which-'isfitte'd 4 patent by novel details of construction and a a rotary three-way valve 23. I

novelarrangement of-parts, as will-'be fully di's- This valve may be rotated from outside the 107 closedinthe course of the iollowingdescription, housing by a tool inserted in cavities 23a, and. and another object isto-providefor-the use ofit may be held in adjusted positions by a settheburner, in cooperation with a source offuelscrew 24. The valve chamber has a port 25 I carrying air currents; communicating with the air-chamber IH which In-the accompanying drawings, in the severalconnects with the passage l 5 -b etwee'n the bur-ner viewsof'which like-parts-are similarly designated, and the combustionchamber, The'valve chamber Figure 1 represents asectional elevation of the also has a port 26 for the admissionof' air from improved burner in its operative position relathe surrounding atmosphere andit base/thi d? tive to the feed opening in thewall of a furnace. port 21 which connects by means of a'flexible con-'- I Figure2 is-a-partially broken front view of the duit 28- with a source of a fuel-carrying air cur- 2i) same-looking in the-directionof the arrow 2-in rent, such as the grinding mill shown at} 29 m Figure 1. Figure6fof the drawings.

Figure 3-is a'fragmentary section on the lin The valvehas three intercommunicatirig" 'p'e-' 3 3 of Figure 1. 1 ripheral openings 30;3I and 32 adapted 'to 'regis' Figure-4 is asectionalview ofa-modification ter with the port ofthe housing. a 25 of the construction shown iii-Figure 1. The burner-block hasa central opening- 33 into Figure-5 is apartiallysectional front elevation which extends a flaring feed nozzle 34, which at of the-construction shown in-Figure l. its small'er'end connects with aconduit- 35con- "Figure 6 is-an elevation drawn toa' reduced necting with the source OffueI-G-ar rying airscale, showing the burner in cooperative assooiarents exemplified by the before-mentioned mill} 30 tionwith a source of fuel-laden air currents. A packing 36 0fnon-conductive'Inaterial sur- Oc'cupying-an opening of the furnace wall, is a rounds" the nozzleinsidethe burner-block; 'At' combustion chamber 5 made up of a conical and the'endof the nozzle inside the block; is a whir1er annular body 6' of refractorymaterial, such as in the form of radial fan-likeib e t r s H fire brick, surrounded by a-bed of rockwool or posite to thenozz'le andthe-Whirler the blockihas 35 other suitable insulating substance 1 Within aafiaring opening38 through-which the filer-laden thinmetal tube- 8, which is fitted in-the opening. aircurrents pass intothe combustion chamber. fla ed plate- 9 of similar material covers Inside the flaring openingsare the terminals'of the front end of the heat resisting y t two con'ductors of electricity 39;-spacd -apart to I surrounding insulation, and an annular plate In provide a spark-gap 4U. 40 covers the insulating material and'a-part of the The conductors extend through openings in body at the inside of the wall. 7 the block which are enlarged-as at4'-l to receive The combustion chamber'thus constructed has G p in 42 y means of Whichth'e conductors anopening' l2 alined'with a passage IS in the are q mi s 'i lead Wires 4 furnace wall for the discharge of ashes; cCmmumcatmg with the i m i i 45 The inner surface of the refractory body of the iccess g a i t o m outsomgthel Y r urner an 1 s ousmg. I

5Q chamber IA of comparatively narrow width. supplemental lgmtlon means 15 provlded' by? A burner is spaced from this chamber to procircular pipe-45' disposed inside theair-chamb'er, in connect-ionwith a source of supply of gaseous vide a passage I5 for air from the chamber l4 into u THE ring has a number 0f'n0z-z1s-or the preliminary combustion chamber. burner-openings 46, facing the passage l5i m The burner comprises a bodyor blockl6- of terr tb thepreliminary coriibustibn chambers. n cotta-or other refractorymaterial mounted in-a. In the'operationof tlie-burnersys'tem; air cur 55 rents carrying finely divided coal or other fuel are conducted through the conduit 35 into the nozzle 34 at a velocity predetermined in the grinding mill or other source. The flaring nozzle, the flaring passage 38 of the burner, the flaring combustion chamber 5, and the whirler 31 cooperate to gradually reduce the velocity of the air currents so that the fuel enters the combustion chamber of the furnace at a comparatively low velocity, which is important since it produces the short flame essential in small furnaces, such as those used in residential heating-systems.

During the passage of the fuel through the burner, it is ignited by the spark in the gap 40 or by the flames issuing from the gas-ring 45. The gas-ring is provided particularly for use in case the coal or other fuel is of low volatile character, to insure its ignition before it enters the combustion chamber. In this instance, the spark will ignite the gas and the flames of the burning gas ignite the coal.

In the use of fuel of higher volatility, the electric spark is suhicient, in itself, to ignite the fuel.

Air in regulatable quantities is admitted to the fuel entering the combustion chamber through the valve-controlled ports 20, which communicate with the air-chamber l9 around the burner, and by means of the passage IS with the combustion chamber. Additional air may be admitted to the air chamber through the ports 26 and 25 when the valve is in the position shown in Figure 3 of the drawings.

The port 21 of the valve housing communicates with the suction line of the source of fuel supply so that a surplus of heated air may be drawn from the combustion chamber to the source for the purpose of preheating the fuel, and of aiding inrconveying the fuel, to the burner by a current of air. Thus a circulatory movement of the air between the source and the combustion chamber is produced.

It will be understood that by further adjustment of the valve, the air-chamber [9 around the burner, may be shut off from the atmosphere at 26, and from the source of fuel-supply.

The valve 23 and the shutter 2| provide means for absolute control of the operation of the burner, and owing to the connections between the combustion chamber and the source as hereinbefore described, the suction of the source may be utilized to regulate the supplyof secondary air to the burner. The air chamber around the burner insulates the latter from the housing in which it is mounted.

The connection between the combustion chamber and the source by way of the valve 23, will harmlessly dispose of the effects of minor ignition explosions and the resulting dust and dirt by sucking the gases back into the mill. It, moreover, lessens the cooling effect of the air upon the ports of the burner system. The fuel ignited in the burner block 16 enters the combustion chamber in a burning condition. The comparatively thin body 6 of the combustion chamber quickly, heats and continues combustion, and the fuel thus enters the combustion chamber of the furnace in a state of combustion throughout, and at the desired low velocity. It is essential that the velocity of the air currents shall not be below that at which the fuel carried by the currents may fall by lack of a sustaining force.

What I claim and desire to secure by Letters Patent is:

1. A burner-system for furnaces, having a combustion chamber, a source of fuel-carrying air currents, a burner communicating with the combustion chamber, a conduit establishing communication between the burner and the source, a conduit for returning heated air-fuel mixtures from the burner to the source, having an opening to the atmosphere, and a three-way valve controlling the last named conduit so as to selectively connect the burner with the atmosphere or with the source.

2. A burner-system for furnaces, having a combustion chamber, a source of fuel-carrying air currents, a burner communicating with the combustion chamber, the burner having a central inwardly flaring opening for the admission of fuel, a conduit providing a communicating passage between the opening and the source, means providing an annular chamber about the burner in communication with the space about the discharge end of the flaring opening, a separate conduit forming a communicating passage between the annular chamber and the source, and means for selectively establishing communication from the annular chamber to the source, or to the atmosphere.

3. A burner-system for furnaces, having a combustion chamber, a source of fuel-carrying air currents, a burner communicating with the combustion chamber, the burner having a central inwardly flaring opening for the admission of fuel, a conduit providing a communicating passage between the opening and the source, means providing an annular chamber about the burner in communication with the space about the discharge end of the flaring opening, a separate conduit forming a communicating passage between the annular chamber and the source, and means for selectively establishing communication from the annular chamber to the source, or to the atmosphere, including a three-way Valve.

4. A burner system for furnaces comprising a furnace wall having an opening whose inner end is in communication with the interior of the furnace, a tubular member forming a combustion chamber and having one end in communication with the interior of the furnace through said opening, a burner in communication with the other end of the tubular member and spaced therefrom to provide a passage for air to the combustion chamber, a housing surrounding the burner having an air chamber in communication with said passage, and having a branched conduit in communication with the chamber, means for connecting the air chamber with either branch to the exclusion of the other, a source of fuel-carrying air, one of the branches communicating directly with the atmosphere, a conduit for establishing communication between the other branch and the source of fuel-carrying air, and a third conduit for establishing a communication between the source and the burner for conveying fuel-carrying air to the burner.

5. In a system for burning finely divided fuel, a burner having a combustion chamber, a source of fuel-carrying air, a conduit extending from the source to the burner for conveying fuel-carrying air to the latter, a housing providing an air chamber about the burner and a passage establishing communication between the air chamber and the combustion chamber, and means including a conduit and a three-way valve for selectively connecting the air chamber to the atmosphere to the exclusion of the source and to the source exclusive of the atmosphere.

6. A burner-system for furnaces, comprising a furnace wall having an opening, a combustion chamber having one end communicating with the interior of the furnace through said opening of the furnace-wall, a burner communicating with the combustion chamber at the other end thereof, and spaced therefrom to provide a passage for air to the combustion chamber, a housing surrounding the burner having an air chamber in communication wtih said passage, and having two conduits communicating with the atmosphere, a. valve controlling one of said two conduits, a source of fuel-carrying air-currents, means establishing communication between said source and the burner,-a conduit to return fuel and air from the housing to the source, and a valve controlling the last-mentioned conduit and the other of said tWo conduits.

7. In a system for burning finely divided fuel comprising a burner, having a combustion chamber for the fuel, a source of fuel-carrying aircurrents connected with the combustion chamber of the burner, means including a conduit having a branch effective to connect the combustion chamber to atmosphere for the supply of air and a branch effective to connect the combustion chamber with said source, for the escape of heated air-fuel mixtures to the source and a valve operable in one position to open one of said branches and operable in another position to open the other of said branches.

8. A burner-system for furnaces, comprising a burner having a combustion chamber, a source of fuel-carrying currents, communicating with said combustion chamber, a housing surrounding the burner and communicating with the combustion chamber thereof, and having a conduit establishing communication between the burner and the source, another conduit for returning aircurrents from the housing to the source, provided with an opening to the atmosphere, and a threeway valve controlling the conduit from said housing to said opening and the source so as to selectively connect the housing with the source and to exclude the opening, to connect said housing with the source and to include the opening and to connect said housing with said opening and to exclude the source.

DURBIN VAN LAW. 

